In the winding of textile yarns, it is well known to guide the yarns to rotating cores while traversing the yarn guides axially of the cores to form windings of the yarns about the cores. Such winding of textile yarns frequently results in two particularly acute problems which are respectively referred to as .-+.hard ends" and "pattern formation."
Hard and, under certain circumstances, thickened places in the yarn packages are frequently formed at opposite ends thereof corresponding to opposite ends of the traverse stroke of the yarn guides. With conventional cylindrical and, to a lesser extent, biconical yarn packages, the yarn windings at opposite ends of the yarn packages become superimposed and with increasing package diameter cause the ends of the package to be harder than the remainder of the package. Under certain circumstances, these superimposed windings also result in the end portions of the package being thicker or having a greater diameter than the remainder of the package so that a cylindrical package build-up cannot be achieved.
There have been previous attempts to overcome this problem by temporarily shortening the traverse stroke of the yarn guides for a few windings in a repetitive pattern. The amount of traverse stroke reduction has been dependent upon the denier of the yarn and reductions of up to 10 mm have occurred. While reducing the degree of thickening and of the hardness of the end portions of such yarn packages, such previous attempts have not been found to completely solve this problem. Rather it has been frequently observed that hardened places form both at the opposite ends of the package and at the places corresponding to the ends of the shortened traverse winding strokes of the yarn guides.
In addition, such previous unsuccessful attempts to solve the "hard ends" problem have not even addressed the problem of "pattern formation" which occurs when, with increasing package diameter, the windings of yarn within the body of the yarn package become superimposed over previously formed windings. The pattern formation problem and one solution thereto are discussed in the copending application, Ser. No. 104,969 of Gerhard Martens, filed Dec. 18, 1979 and entitled METHOD AND APPARATUS FOR WINDING TEXTILE YARNS which is assigned to the same assignee as is this application. While solving the "pattern formation" problem, the method and apparatus of this copending application does not solve nor even address the "hard ends" problem.